Effect of cantilever extension on marginal bone loss around implants supporting All-on-4 CAD/CAM screw-retained prostheses (A Randomized Controlled Clinical Trial)

Al-Sadat, Omar Abbas; Soliman, Sara Ibrahim; Abdel Aal, Mohamed Abdel Hakim

doi:10.21608/asdj.2024.340781.1680

Effect of cantilever extension on marginal bone loss around implants supporting All-on-4 CAD/CAM screw-retained prostheses (A Randomized Controlled Clinical Trial)

Document Type : Consort randomized clinical trials (RCT)

Authors

¹ Oral and Maxillofacial Prosthodontics,Faculty of Dentistry, Ain Shams University

² oral and maxillofacial prosthodontics, faculty of dentistry, Ain shams universitty

³ Oral and Maxillofacial Prosthodontics Department, Faculty of Dentistry, Beni-Suef University.

10.21608/asdj.2024.340781.1680

Abstract

Aim: To evaluate the effect of cantilever extension on peri-implant marginal bone loss in patients restored by immediately-loaded CAD/CAM All-on-4 definitive prostheses with PEEK superstructure.
Materials & Methods: 112 implants were placed according to All-on-4 concept principles in maxillary and mandibular arches for fourteen edentulous patients (eight implants for each patient, four implants per arch). Patients were divided into two equal groups at random (n=7) and were immediately restored by CAD/CAM screw-retained PEEK-Resin prosthesis constructed without cantilever extension for group I and with one-unit cantilever extension for group II. A follow-up protocol of 6, 9, and 12 months was scheduled to assess the peri-implant marginal bone loss (MBL). The independent t-test was used to compare MBL between the groups, the Repeated measures ANOVA was used to compare bone loss between follow-ups, and intragroup comparison between maxilla and mandible was performed using the Paired t-test (P≤0.05). Results: For both arches and at all the study intervals, the independent t-test revealed a significantly higher bone loss in the cantilever group II than in group I without a cantilever (P<0.05). Both groups showed significant increases in bone loss over time (p<0.001). The average bone loss around maxillary implants was significantly higher than around mandibular implants in both groups at all intervals (P<0.05).
Conclusion: Immediately loaded CAD/CAM PEEK-Resin prostheses constructed with cantilever extension induce greater peri-implant bone loss compared to prostheses without cantilevers, however, both can provide predictable results if appropriate guidelines for treatment planning, implant placement, prosthesis designing, and fabrication are strictly followed.

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